The invention concerns a fire arm with improved salvo accuracy.
In particular, the invention concerns a fire arm of the machine-gun type which can fire by bursts, whereby the fire arm comprises a barrel and a casing mounted on a supporting frame, whereby the frame comprises a cradle provided with a slide which can slide in a direction which is mainly parallel to the axis of the barrel, whereby the casing is mounted on the slide of the cradle by means of a transversal hinge pin on the one hand, and on the frame by means of at least one shoe mounted in a sliding guide provided in the frame on the other hand.
The arm can be mounted with its frame on a tripod, on a remote-controlled turret or any other support whatsoever.
The casing and the barrel can move in the axial direction of the barrel, whereby the casing is supported by the slide of the cradle and by the shoe which is held in the sliding guide of the frame which, in the case of the known arms, is parallel to the axis of the barrel.
In rest, the slide of the cradle is maintained in an intermediary position by means of a spring or several springs.
While firing, the slide and the shoe allow for a guided recoil of the arm through the effect of the reactive forces of the propulsion gases of the ammunition that is being fired, and the spring or springs, either or not assisted by one or several shock absorbers, make it possible to dampen the axial to-and-fro movement of the casing while firing by bursts, and to stabilize the position of the casing around an average axial position.
The hinge pin of the casing on the frame allows the casing and the barrel to tilt.
When firing by bursts, the first shot is fired in the rest position of the arm, as when firing shot by shot, and the arm recoils due to the impulse of the first shot.
Immediately after the first shot and during the following shots, the barrel puts itself in position as the mobile elements of the arm and the interface elements such as the shoe connect again, and it puts itself in an average raised and diverted position around which the barrel oscillates through the effect of the successive shots.
Said oscillation of the barrel contributes to the dispersion of the firing impacts around an average point of impact which forms the centre in which the impacts of the successive shots come together at the first salvo.
In the case of the known fire arms we observe a deviation between the initial point of impact of the first shot and the average point of impact of the successive shots, which is translated in a diminished shooting accuracy, as all the salvos are taken into account, including the first shot.